Voice coil motor

ABSTRACT

A VCM (voice coil motor) is disclosed, the VCM including: a rotor including a lens-accommodating, both ends opened cylindrical bobbin and a coil block including a coil wound on a periphery of the bobbin; a stator including a cylindrical yoke formed with a lens-exposing opening, a plurality of magnets disposed inside the yoke and opposite to the coil block, and a housing disposed inside the yoke to fix the plurality of magnets; and an elastic member elastically supporting the bobbin.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.17/129,305, filed Dec. 21, 2020; which is a continuation of U.S.application Ser. No. 16/219,497, filed Dec. 13, 2018, now U.S. Pat. No.10,914,914, issued Feb. 9, 2021; which is a continuation of U.S.application Ser. No. 15/399,447, filed Jan. 5, 2017, now U.S. Pat. No.10,185,117, issued Jan. 22, 2019; which is a continuation of U.S.application Ser. No. 14/884,349, filed Oct. 15, 2015, now U.S. Pat. No.9,575,283, issued Feb. 21, 2017; which is a continuation of U.S.application Ser. No. 14/457,984, filed Aug. 12, 2014, now U.S. Pat. No.9,190,891, issued Nov. 17, 2015; which is a continuation of U.S.application Ser. No. 13/193,706, filed Jul. 29, 2011, now U.S. Pat. No.8,836,177, issued Sep. 16, 2014; which claims the benefit under 35U.S.C. § 119 of Korean Application Nos. 10-2010-0074002, filed Jul. 30,2010; 10-2010-0087943, filed Sep. 8, 2010; 10-2010-0115163, filed Nov.18, 2010; and 10-2010-0121320, filed Dec. 1, 2010; all of which arehereby incorporated by reference in their entirety.

BACKGROUND OF THE DISCLOSURE Field of the Disclosure

The present disclosure relates to a voice coil motor (VCM).

Discussion of the Related Art

Recently, a mobile phone mounted with a super-small high resolutiondigital camera has been developed. The super-small digital cameramounted on the mobile phone includes an image sensor changing an outsidelight to an image and a lens opposite to the image sensor.

The conventional super-small digital camera is fixedly mounted with thelens and the image sensor to have a trouble in obtaining a high qualityimage due to difficulty in adjusting a distance between the image sensorand the lens.

Recently, a lens driving device such as a voice coil motor has beendeveloped to adjust a distance between a lens and an image sensor. Thevoice coil motor generally includes a bobbin secured with a lens, a coilblock wound on a periphery of the bobbin, a magnet opposite to the coilblock, a yoke securing the magnet, and a leaf spring elasticallysupporting the vertically-moving bobbin.

The magnet, one of the essential components of the conventional voicecoil motor, is secured to an inner lateral surface of the yoke using anadhesive. However, in a case the magnet is secured to the inner lateralsurface of the yoke using an adhesive, the magnet is separated from theyoke by a strong shock or a vibration applied to the yoke, and if themagnet is separated from the yoke, the bobbin is generated with aproblem of defective driving.

Another problem encountered by the conventional voice coil motor is thata yoke is needed to secure a yoke the magnet opposite to the bobbinwhereby the number of parts and assembly processes is increased

Still another problem is that an aperture of the lens mounted on thebobbin cannot be increased due to an area occupied by the bobbin and themagnet.

BRIEF SUMMARY

The present disclosure is directed to cope with the abovementionedproblems and to provide a VCM (voice coil motor) configured to inhibitmovement of a magnet inside a yoke by outside shock and vibration.

Technical problems to be solved by the present disclosure are notrestricted to the above-mentioned description, and any other technicalproblems not mentioned so far will be clearly appreciated from thefollowing description by the skilled in the art.

In one general aspect of the present disclosure, there is provided aVCM, (voice coil motor) comprising: a rotor including alens-accommodating, both ends opened cylindrical bobbin and a coil blockincluding a coil wound on a periphery of the bobbin; a stator includinga cylindrical yoke formed with a lens-exposing opening, a plurality ofmagnets disposed inside the yoke and opposite to the coil block, and ahousing disposed inside the yoke to fix the plurality of magnets; and anelastic member elastically supporting the bobbin.

In another general aspect of the present disclosure, there is provided aVCM (voice coil motor), comprising: a rotor including alens-accommodating, both ends opened cylindrical bobbin and a coil blockincluding a coil wound on a periphery of the bobbin; a stator includinga plurality of flat magnets opposite to the coil block and a yoke formedwith pocket units fixing both lateral surfaces of each flat magnet and arear surface opposite to a front surface opposite to the coil block; andelastic member elastically supporting the bobbin.

In still another general aspect of the present disclosure, there isprovided a VCM (voice coil motor), comprising: a rotor including abobbin having a hollow hole mounted with a lens and a coil blockarranged at a periphery of the bobbin; an elastic member elasticallycoupled to the bobbin; and a stator including an upper plate exposingthe hollow hole, a housing including a lateral plate extended from anedge of the upper plate to encompass the rotor and formed with anaccommodation hole, and a flat magnet secured to the accommodation hole,wherein the housing includes a disengagement prevention unit inhibitingthe flat magnet from being disengaged from the lateral plate to adirection facing the coil block.

In still another general aspect of the present disclosure, there isprovided a VCM (voice coil motor) comprising: a rotor including alens-mounted bobbin and a coil block arranged at a periphery of thebobbin; a stator including a flat magnet arranged at a periphery of thecoil block and a bottom spacer securing the flat magnet; an elasticmember elastically supporting the bobbin; and a base in which the rotor,the bottom spacer and the elastic member are secured.

The VCM according to exemplary embodiments of the present disclosure hasan advantageous effect in that a magnet arranged inside a yoke ispress-fitted using a housing to inhibit a reduced driving efficiency anda driving imperfection of a rotor generated by movement of the magnetinside the yoke.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the present disclosure and are incorporated in thepresent disclosure and constitute a part of this application, andtogether with the description, serve to explain the principle of thedisclosure. In the drawings:

FIG. 1 is an exploded perspective view illustrating a VCM according toan exemplary embodiment of the present disclosure;

FIG. 2 is an exploded perspective view of a stator in FIG. 1 ;

FIG. 3 is a coupled perspective view of a stator in FIG. 2 ;

FIG. 4 is a cross-sectional view of line ‘I-I′’ in FIG. 3 ;

FIG. 5 is a perspective view illustrating a housing of a stator of a VCMaccording to another exemplary embodiment of the present disclosure;

FIG. 6 is a perspective view illustrating a housing of a stator of a VCMaccording to still another exemplary embodiment of the presentdisclosure;

FIG. 7 is a cross-sectional view illustrating a stator of a VCMaccording to still another exemplary embodiment of the presentdisclosure;

FIG. 8 is an exploded perspective view illustrating a VCM according toan exemplary embodiment of the present disclosure;

FIG. 9 is an exploded perspective view of magnet and bobbin of stator ofFIG. 8 ;

FIG. 10 is a plan view of FIG. 9 ;

FIG. 11 is a plan view of a yoke and a magnet of VCM according toanother exemplary embodiment of the present disclosure;

FIG. 12 is an exploded perspective view of a VCM according to anexemplary embodiment of the present disclosure;

FIG. 13 is an assembled cross-sectional view of FIG. 12 ;

FIG. 14 is a cross-sectional view cut along line I-I′ of FIG. 12 ;

FIG. 15 , FIG. 16 , and FIG. 17 illustrates front views of lateral plateof FIG. 14 ;

FIG. 18 is a cross-sectional view of a disengagement prevention unit ofa housing according to an exemplary embodiment of the presentdisclosure;

FIG. 19 a cross-sectional view of a disengagement prevention unit of ahousing according to another exemplary embodiment of the presentdisclosure;

FIG. 20 is an exploded perspective view of a VCM according to anexemplary embodiment of the present disclosure;

FIG. 21 is an exploded perspective view of a flat magnet and a bottomspacer in FIG. 20 ;

FIG. 22 is an assembled perspective view of a flat magnet and a bottomspacer in FIG. 21 ; and

FIG. 23 is a front view of a flat magnet coupled to the bottom spacer ofFIG. 22 .

DETAILED DESCRIPTION

Advantages and features of the present invention may be understood morereadily by reference to the following detailed description of exemplaryembodiments and the accompanying drawings. Detailed descriptions ofwell-known functions, configurations or constructions are omitted forbrevity and clarity so as not to obscure the description of the presentdisclosure with unnecessary detail. Thus, the present disclosure is notlimited to the exemplary embodiments which will be described below, butmay be implemented in other forms. In the drawings, the width, length,thickness, etc. of components may be exaggerated or reduced for the sakeof convenience. Furthermore, throughout the descriptions, the samereference numerals will be assigned to the same elements in theexplanations of the figures, and explanations that duplicate one anotherwill be omitted. Accordingly, the meaning of specific terms or wordsused in the specification and claims should not be limited to theliteral or commonly employed sense, but should be construed or may bedifferent in accordance with the intention of a user or an operator andcustomary usages. Therefore, the definition of the specific terms orwords should be based on the contents across the specification.

The terms “first,” “second,” and the like, herein do not denote anyorder, quantity, or importance, but rather are used to distinguish oneelement from another, and the terms “a” and “an” herein do not denote alimitation of quantity, but rather denote the presence of at least oneof the referenced item.

As may be used herein, the terms “substantially” and “approximately”provide an industry-accepted tolerance for its corresponding term and/orrelativity between items. Such an industry-accepted tolerance rangesfrom less than one percent to ten percent and corresponds to, but is notlimited to, component values, angles, et cetera. Such relativity betweenitems ranges from less than one percent to ten percent.

FIG. 1 is an exploded perspective view illustrating a VCM according toan exemplary embodiment of the present disclosure, FIG. 2 is an explodedperspective view of a stator in FIG. 1 , FIG. 3 is a coupled perspectiveview of a stator in FIG. 2 , and FIG. 4 is a cross-sectional view ofline ‘I-I′’ in FIG. 3 .

Referring to FIG. 1 , a VCM (800) includes a rotor (100), an elasticmember (200) and a stator (300). The VCM (800) may further include acase (400), a cover can (600) and a spacer (700).

The rotor (100) includes a bobbin (150) and a coil block (190). Thebobbin (150) takes the shape of both ends-opened barrel. The bobbin maytake the shape of both ends-opened cylinder, for example. The bobbinserves to secure a lens opposite to an image sensor changing an outsidelight to an image.

An inner surface of the bobbin (150) is formed with a female screw unit(112) for accommodating the lens to the bobbin, and the female screwunit (112) may be formed with a lens fixing member (not shown) coupledto the lens.

Alternatively, it should be also appreciated that the lens is directlycoupled to the female screw unit of the bobbin (150). A peripheralbottom distal end of the bobbin (150) is formed with a hitching sill(118) for supporting a coil block (190, described later).

The coil block (190) is arranged at a periphery of the bobbin (150), andsecured by using the hitching sill (118) formed at the peripheral bottomof the bobbin (150).

The coil block (190) may be formed by winding a coil on the periphery ofthe bobbin (150) in the shape of a cylinder, or by inserting acylindrically wound coil block (190) to the periphery of the bobbin(150). In a case the coil block (190) is formed by inserting acylindrically wound coil block (190) to the periphery of the bobbin(150), an adhesive may be interposed between the coil block (190) andthe bobbin (150).

The coil block (190) is electrically connected to first elastic members(210) of elastic member (200, described later), and a magnetic field isgenerated from the coil block (190) by a driving signal provided fromthe first elastic members (210). The rotor (100) is driven relative to amagnet (350) by a force generated by a magnetic field of the coil block(190) and a magnetic field of the magnet (350, described later).

In the exemplary embodiment of the present disclosure, a gap between alens mounted on the bobbin (150) and an image sensor (not shown)opposite to the lens can be accurately adjusted by adjusting a level ofa driving signal applied to the coil block (190).

The elastic member (200) includes a first elastic member (210) and asecond elastic member (220). In the exemplary embodiment of the presentdisclosure, each of the first elastic member (210) and the secondelastic member (220) may include a leaf spring.

The first elastic member (210) and the second elastic member (220)according to the exemplary embodiment of the present disclosure serve toelastically support the bobbin (150), inhibit the bobbin (150) frombeing disengaged from a predetermined position, and return the bobbin(150) lifted by the coil block (190) and the magnet (350) to an initialposition.

The first elastic member (210) is coupled to a bottom surface (117) ofthe bobbin (150). The first elastic member (210) is coupled to a boss(not shown) protruded from the bottom surface (117) of the bobbin (150).The first elastic member (210) includes a through hole coupled to theboss protruded from the bottom surface (117) of the bobbin (150). Adistal end of the boss is applied with heat and pressure after the firstelastic member (210) is inserted into the boss protruded from the bottomsurface (117) of the bobbin (150). An upper surface of the first elasticmember (210) is secured to the boss by the distal end of the boss fusedby the heat and pressure applied to the boss, whereby the first elasticmember (210) is inhibited from being disengaged from the bottom surface(117) of the bobbin (150).

The first elastic member (210) may be formed in a pair according to theexemplary embodiment of the present disclosure, and the pair of firstelastic members (210) is mutually electrically insulated therebetween,and the electrically insulated pair of first elastic members (210)includes a connection terminal which is in turn electrically connectedto an outside circuit substrate.

One distal end of the coil forming the coil block (190) and the otherdistal end facing the one distal end of the coil are electricallyconnected to the pair of first elastic members (210). As a result, thedriving signal provided from the outside circuit substrate is providedto the coil block (190) through the first elastic members (210), and amagnetic field is generated from the coil block (190) by the drivingsignal.

The second elastic member (220) is coupled to an upper surface (116)opposite to the bottom surface (117) of the bobbin (150).

Referring to FIGS. 2, 3 and 4 , the stator (300) includes a yoke (310),a magnet (350) and a housing (370) (for example, a magnet fixing memberstyle housing). The yoke (310) includes an upper plate (312) and alateral plate (314). The upper plate (312) and the lateral plate (314)may include a metal.

The yoke (310) including the metal serves to inhibit a magnetic fluxgenerated from the magnet (350, described later) from leaking, andinduce the magnetic flux generated from the magnet (350, describedlater) to direct to the coil block (190), whereby a driving efficiencyof the rotor (100) can be further enhanced.

An upper plate (312) of the yoke (310) takes the shape of a squareplate, for example, and the yoke (310) is centrally formed with anopening (311) exposing the lens mounted on the bobbin (150). The lateralplate (314) of the yoke (310) is extended from each edge of the upperplate (312) to a direction encompassing the coil block (190), where theupper plate (312) and the lateral plate (314) of the yoke (312) areintegrally formed.

In the exemplary embodiment of the present disclosure, each of themagnets (350) takes the shape of a cuboidal plate, for example, and isarranged at an inner lateral surface of the lateral plate (314) of theyoke (310). For example, in a case four lateral plates (314) including afirst lateral plate (314-1), a second lateral plate (314-2), a thirdlateral plate (314-3), and a fourth lateral plate (314-4) of the yoke(310) are formed, each of four magnets (350) is arranged at each of thefour lateral plates (314-1 to 314-4). Each of the magnets (350) isarranged to face the coil block (190).

In the exemplary embodiment of the present disclosure, the cuboidalmagnets (350) are arranged in parallel with each of the lateral plates(314), and each of the magnets (350) is arranged adjacent to the innerlateral surface of the lateral plate (314). Each of the magnets (350)comprises a first lateral surface (350-1) facing a coil, a secondlateral surface (350-2) facing the coupling unit (374), a third lateralsurface (350-3) disposed opposite to the first lateral surface (350-1),a fourth lateral surface (350-4) disposed opposite to the second lateralsurface (350-2), an upper surface (350-5) facing the body (372), and alower surface (350-6) disposed opposite to the upper surface (350-5).The each of the magnets (350) generates magnetic field, and a forcegenerated by a magnetic field generated by the each magnet (350) and amagnetic field generated by the coil block (190) opposite to the magnets(350) drives the rotor (100).

A housing (370) secures the magnets (350) arranged inside the yoke(310). In the exemplary embodiment of the present disclosure, themagnets (350) can be inhibited from being moved or being disengaged fromdesignated positions by shock or vibration applied from outside, bybeing fixed to the housing (370).

The housing (370) includes a body unit (372) and a coupling unit (374).The body unit (372) is arranged at an inner lateral surface of the upperplate (312) of the yoke (310), and takes the shape of an opening-formedframe. The opening of the body unit (372) takes the shape and sizeappropriate enough not to expose the lens of the bobbin (150). The bodyunit (372) serves as a base for securing the coupling unit (374) to apredetermined position.

In the exemplary embodiment of the present disclosure, the body unit(372) takes the shape of a square frame, for example. The body unit(372) may take various shapes based on arrangement of magnets (350)disposed inside the yoke (310). For example, in a case four magnets,each having the shape of a cuboidal plate, are arranged in a squareshape, the body unit (372) takes the shape of a square frame.Alternatively, in a case a plurality of magnets, each having a curvedplate shape, is arranged in a circle, the body unit (372) takes theshape of a circular frame.

A plurality of coupling units (374) is protruded from the body unit(372) along the lateral plate (314) of the yoke (310) and can include afirst coupling unit (374 a 1), a second coupling unit (374 a 2), a thirdcoupling unit (374 a 3), and a fourth coupling unit (374 a 4). Each ofthe coupling units (374) is formed at a position corresponding to a pairof magnets (350) adjacent to the magnets (350) arranged along thelateral plates (314) of yoke (310). The coupling units (374) and themagnets (350) are mutually coupled by press-fitting method. The couplingunit (374) comprises a first surface (374-1) facing a coil and a secondsurface (374-2) disposed opposite the first surface (374-1). Inaddition, the coupling unit (374) further comprises a third surface(374-3) coupled with the fourth lateral plate (314-4), a fourth surface(374-4) coupled with the first lateral plate (314-1), fifth (374-5) andsixth (374-6) surfaces facing the magnets 350, and a first bottomsurface (374-9) disposed opposite to the body (372). The second surface(374-2) connects the third surface (374-3) and the fourth surface(374-4). An adjacent coupling unit (374) can comprise a seventh surface(374-7) facing the coil, an eighth surface (374-8) disposed opposite tothe seventh surface (374-7), and a second bottom surface (374-10)disposed opposite to the body (372). It is noted that the surfaces(374-1-374-9) of the coupling unit (374), the lateral plates(314-1-314-4) of the yoke (310), and other elements are labeled (e.g.,“first”, “second”) for convenience of differentiating items from eachother, and the labels are applied arbitrarily (i.e., the “third” surface(374-3) can be thought of as a “first” surface, etc.). The yoke (310)can include corner parts (310 a, 310 b, 310 c, and 310 d) disposedbetween adjacent lateral plates (i.e., corner part (310 a) is disposedbetween the first lateral plate (314-1) and the fourth lateral plate(314-4)). The second surface (374-2) of the first to fourth couplingunits (374 a 1, 374 a 2, 374 a 3, 374 a 4) can respectively correspondto the corner parts (310 a, 310 b, 310 c, 310 d). The second surface(374-2) of each coupling unit (374) can be spaced apart from itscorresponding corner part (310 a, 310 b, 310 c, and 310 d) by a gap (g),as seen in FIG. 3 and labeled for exemplary purposes between the secondcoupling unit (374 a 2) and the corresponding corner part (310 b).

In the exemplary embodiment of the present disclosure, each of thecoupling units (374) protruded from the body unit (372) is protruded inthe shape of a rectangular pillar, and the magnets (350) arranged inparallel with the lateral plates (314) of the yoke (310) and therectangular pillar-shaped coupling units (374) are mutually formed at anobtuse angle.

To be more specific, the angle formed by the coupling unit (374) and themagnets (350) may be 135°, for example. Both lateral walls of thecoupling unit (374) opposite to each distal end of the adjacent pair ofmagnets (350) are formed with coupling grooves (375) for being coupledwith distal ends of the magnets (350).

In the exemplary embodiment of the present disclosure, the magnet (350)is coupled to the coupling unit (374) by allowing the magnets (350) tobe press-fitted into the coupling grooves (375) to a direction facing abottom surface of the coupling unit (374) from an upper surface of thecoupling unit (374).

In the exemplary embodiment of the present disclosure, the press-fittingmethod may be categorized into three types based on dimensionalrelationship of the coupling grooves (375) and the magnets (350), thatis, a forced press-fitting method where there is no gap between thecoupling groove (375) and the magnet (350), a middle press-fittingmethod where there is a gap or no gap between the coupling groove (375)and the magnet (350), and a loose press-fitting method where there isalways a gap between the coupling groove (375) and the magnet (350). Inthe exemplary embodiment of the present disclosure, all the structuralmethods may be included capable of inhibiting vertical or horizontalmovement of the magnet within a predetermined range.

In the exemplary embodiment of the present disclosure, as the magnets(350) are coupled to the coupling groove (375) to a direction from theupper surface of the coupling unit (374) to a bottom surface of thecoupling unit (374), the magnets (350) can be secured to a predeterminedposition without moving to a direction facing the coil block (19) evenif there is a strong shock or vibration from outside.

In the exemplary embodiment of the present disclosure, the body unit(372) and the coupling unit (374) of the housing (370) fixing the magnet(350) include a synthetic resin capable of injection molding, where thebody unit (372) and the coupling unit (374) are integrally formed by theinjection molding.

Although the exemplary embodiment of the present disclosure hasexplained that the housing (370) can be formed by the injection moldingof synthetic resin, the housing (370) can be alternatively formed bypress work of a light metal.

Although the magnet (350) secured to the housing (370) has a structureof easily being disengaged to the upper surface of the coupling unit(374), the magnet (350) secured to the housing (370) is brought intocontact with the spacer (700) of FIG. 1 , and the spacer (700) inhibitsthe magnet (350) from being disengaged from the housing (370), wherebythe magnet (350) becomes vertically fixed.

Meanwhile, the housing (370) may be simply contacted to the innerlateral surface of the upper plate (312) of yoke (310), an adhesive(378) may be arranged between the housing (370) and the inner lateralsurface of the upper plate (312) of yoke (310) in order to inhibit thehousing (370) from moving inside the yoke (310). Alternatively, itshould be apparent that a concave groove for inserting the body unit(372) may be formed at the upper plate (312) contacted by the body unit(372) of the housing (370) in order to securing the housing (370) to theupper plate (312) of the yoke (310).

FIG. 5 is a perspective view illustrating a housing of a stator of a VCMaccording to another exemplary embodiment of the present disclosure.

The VCM illustrated in FIG. 5 has the substantially same structure asthat of FIGS. 1 to 4 except for the coupling unit of the housing, suchthat like reference numerals refer to like elements throughout, andexplanations that duplicate one another will be omitted.

Referring to FIG. 5 , the housing (370) includes a body unit (372) and acoupling unit (374 a). The coupling unit (374 a) is protruded from thebody unit (372) along the lateral plate (314) of the yoke (310) andtakes the shape of a triangular pillar. Two lateral surfaces of thecoupling unit (374 a) having the triangular pillar shape are arrangedparallel with an adjacent pair of lateral plates (314) and formed withcoupling grooves (375 a) to be coupled to the magnets (350) in thepress-fitting method.

FIG. 6 is a perspective view illustrating a housing of a stator of a VCMaccording to still another exemplary embodiment of the presentdisclosure.

The VCM illustrated in FIG. 6 has the substantially same structure asthat of FIGS. 1 to 4 except for the coupling unit of the housing, suchthat like reference numerals refer to like elements throughout, andexplanations that duplicate one another will be omitted.

Referring to FIG. 6 , the housing (370) includes a body unit (372) and acoupling unit (374 b). The coupling unit (374 b) is protruded from thebody unit (372) along the lateral plate (314) of the yoke (310) andtakes the shape of a circular cylinder. A periphery of the coupling unit(374 b) having the circular cylinder shape is arranged with a couplinggroove (375 b) to be coupled to the magnets (350) in the press-fittingmethod.

FIG. 7 is a cross-sectional view illustrating a stator of a VCMaccording to still another exemplary embodiment of the presentdisclosure.

The VCM illustrated in FIG. 7 has the substantially same structure asthat of FIGS. 1 to 4 except for the coupling unit of the housing, suchthat like reference numerals refer to like elements throughout, andexplanations that duplicate one another will be omitted.

Referring to FIG. 7 , the housing (370) includes a body unit (372) and amagnet insertion groove (372 a).

In the exemplary embodiment of the present disclosure, the body unit(372) takes the shape of a square frame that is brought into contactwith an inner lateral surface of the upper plate (312) of yoke (310),and is formed at an upper surface opposite to the inner lateral surfaceof the upper plate (312) of yoke (310) with the magnet insertion groove(372 a) adequate enough to accommodate the magnet (350). Depth of themagnet insertion groove (372 a) is preferably formed with a depth deepenough to inhibit the magnet (350) from being disengaged from the bodyunit (372).

In the exemplary embodiment of the present disclosure, the body unit(372) is formed with the magnet insertion groove (372 a) into which themagnet (350) is inserted, whereby the magnet (350) can be securely fixedto the body unit (372) without forming a coupling unit that is coupledto the magnet (350).

Although the exemplary embodiment of the present disclosure hasillustrated and explained that the magnet (350) is coupled viapress-fitting method to the injection-molded frame in the yoke (310), itshould be apparent that a part of the upper plate of the yoke is cut outand bent to form a housing for securing the magnet (350) to the upperplate (312) of the yoke and the housing is coupled to the magnet (350).

Referring to FIG. 1 again, the case (400) includes an upper case (410)and a bottom case (420). The case (400) serves to mutually couple andfix the rotor (100), the elastic member (200) and the stator (300). Theupper case (410) includes an upper plate (411) and a coupling pillar(412). The upper case (310) is arranged on an upper surface of the yoke(310), and the second elastic member (220) in the elastic member (200)is interposed between the upper case (410) and the yoke (310).

The upper plate (411) of the upper case (310) takes the shape of asquare plate when viewed from a top plan view, and is centrally formedwith an opening (414) for exposing the bobbin (150).

The coupling pillar (412) of the upper case (410) is protruded inparallel with the bobbin (150) from the four corners of the upper plate(411), and is coupled to the bottom case (420, described later). Thebottom case (420) includes pillars (424) coupled to each coupling pillar(412) of the upper case (410).

As noted from the foregoing, there is an advantageous effect in that thedriving efficiency reduction and driving imperfection of the rotorgenerated by movement of magnet inside the yoke can be inhibited bycoupling the magnet arranged inside the yoke using the housing viapress-fitting method.

Now, another exemplary embodiment of the present disclosure will bedescribed with reference to the accompanying drawings.

In the drawings, the width, length, thickness, etc. of components may beexaggerated or reduced for the sake of convenience. Furthermore,throughout the descriptions, the same reference numerals will beassigned to the same elements in the explanations of the figures, andexplanations that duplicate one another will be omitted. Accordingly,the meaning of specific terms or words used in the specification andclaims should not be limited to the literal or commonly employed sense,but should be construed or may be different in accordance with theintention of a user or an operator and customary usages. Therefore, thedefinition of the specific terms or words should be based on thecontents across the specification.

FIG. 8 is an exploded perspective view illustrating a VCM according toan exemplary embodiment of the present disclosure, FIG. 9 is an explodedperspective view of magnet and bobbin of stator of FIG. 8 , and FIG. 10is a plan view of FIG. 9 .

Referring to FIG. 8 , a VCM (800) includes a rotor (100), an elasticmember (200) and a stator (300). The VCM (800) may further include anupper spacer (400), a cover can (600) and a base (420).

The rotor (100) includes a bobbin (150) and a coil block (190). Thebobbin (150) takes the shape of both ends-opened barrel. The bobbin maytake the shape of both ends-opened cylinder, for example. The bobbinserves to secure a lens opposite to an image sensor changing an outsidelight to an image.

An inner surface of the bobbin (150) is formed with a female screw unit(112) for accommodating the lens to the bobbin (150), and the femalescrew unit (112) may be formed with a lens fixing member (not shown)coupled to the lens.

Alternatively, it should be also appreciated that the lens is directlycoupled to the female screw unit of the bobbin (150). A peripheralbottom distal end of the bobbin (150) is formed with a hitching sill(115) for supporting a coil block (190, described later).

The coil block (190) is arranged at a periphery of the bobbin (150), andsecured by using the hitching sill (118) formed at the peripheral bottomof the bobbin (150).

The coil block (190) may be formed by winding a coil on the periphery ofthe bobbin (150) in the shape of a cylinder, or by inserting acylindrically wound coil block (190) to the periphery of the bobbin(150). In a case the coil block (190) is formed by inserting acylindrically wound coil block (190) to the periphery of the bobbin(150), an adhesive may be interposed between the coil block (190) andthe bobbin (150).

The coil block (190) is electrically connected to first elastic members(210) of elastic member (200, described later). The rotor (100) isdriven relative to a magnet (350) by a force generated by a magneticfield of the coil block (190) and a magnetic field of the magnet (350,described later).

In the exemplary embodiment of the present disclosure, a gap between alens mounted on the bobbin (150) and an image sensor (not shown)opposite to the lens can be accurately adjusted by adjusting a level ofa driving signal applied to the coil block (190).

The elastic member (200) includes a first elastic member (210) and asecond elastic member (220). In the exemplary embodiment of the presentdisclosure, each of the first elastic member (210) and the secondelastic member (220) may include a leaf spring.

The first elastic member (210) and the second elastic member (220)according to the exemplary embodiment of the present disclosure serve toelastically support the bobbin (150), inhibit the bobbin (150) frombeing disengaged from a predetermined position, and return the bobbin(150) lifted by the coil block (190) and the magnet (350) to an initialposition.

The first elastic member (210) is coupled to a bottom surface (117) ofthe bobbin (150). The first elastic member (210) is coupled to a boss(not shown) protruded from the bottom surface (117) of the bobbin (150).The first elastic member (210) includes a through hole coupled to theboss protruded from the bottom surface (117) of the bobbin (150).

A distal end of the boss is applied with heat and pressure after thefirst elastic member (210) is inserted into the boss protruded from thebottom surface (117) of the bobbin (150). An upper surface of the firstelastic member (210) is secured to the boss by the distal end of theboss fused by the heat and pressure applied to the boss, whereby thefirst elastic member (210) is inhibited from being disengaged from thebottom surface (117) of the bobbin (150).

The first elastic member (210) may be formed in a pair according to theexemplary embodiment of the present disclosure, and the pair of firstelastic members (210) is mutually electrically insulated therebetween,and the electrically insulated pair of first elastic members (210)includes a connection terminal which is in turn electrically connectedto an outside circuit substrate.

One distal end of the coil forming the coil block (190) and the otherdistal end facing the one distal end of the coil are electricallyconnected to the pair of first elastic members (210). As a result, thedriving signal provided from the outside circuit substrate is providedto the coil block (190) through the first elastic members (210), and amagnetic field is generated from the coil block (190) by the drivingsignal.

The second elastic member (220) is coupled to an upper surface (116)opposite to the bottom surface (117) of the bobbin (150).

Referring to FIGS. 9 and 10 , the stator (300) includes a yoke (310) anda magnet (350). In the exemplary embodiment of the present disclosure,the magnet (350) includes four magnets, for example. Hereinafter, thefour magnets (350) are defined as a first magnet (352), a second magnet(354), a third magnet (356) and a fourth magnet (358).

The first, second, third and fourth magnets (352, 354, 356, 358) arearranged about the coil block (190), where the first magnet (352) isarranged opposite to the third magnet (356), and the second magnet (354)is arranged opposite to the fourth magnet (358). The first, second,third and fourth magnets (352, 354, 356, 358) are mutually andvertically arranged.

In the exemplary embodiment of the present disclosure, each of thefirst, second, third and fourth magnets (352, 354, 356, 358) includes aninner lateral surface (350 a) facing the coil block (190), an outerlateral surface (350 b) opposite to the inner lateral surface (350 a),and a lateral surface (350 c) connecting the inner and outer lateralsurfaces (350 a, 350 b).

The yoke (310) includes lateral plates (311, 312, 313, 314), and thenumber of the lateral plates (311, 312, 313, 314) is formedcorresponding to that of the magnet (350). The yoke (310) includes ametal material and improves a driving efficiency of the rotor (100) byinhibiting the magnetic flux generated by the magnet (350, describedlater) from leaking and by inducing the magnetic flux generated by themagnet (350) to face the coil block (190).

In the exemplary embodiment of the present disclosure, the yoke (310) isalso formed with four lateral plates (311, 312, 313, 314), because thecoil block (190) is arranged thereabout with the first, second, thirdand fourth magnets (352, 354, 356, 358).

In the exemplary embodiment of the present disclosure, the yoke (310)may take the shape of a square frame when viewed in a top plane view.

Hereinafter, the four lateral plates (311, 312, 313, 314) of the yoke(310) are respectively defined as a first lateral plate (311), a secondlateral plate (312), a third lateral plate (313) and a fourth lateralplate (314).

The first lateral plate (311) is arranged at a position corresponding tothe first magnet (352), the second lateral plate (312) is arranged at aposition corresponding to the second magnet (354), the third lateralplate (313) is arranged at a position corresponding to the third magnet(356) and the fourth lateral plate (314) is arranged at a positioncorresponding to the fourth magnet (358).

An external surface (350 b) of the first magnet (352) is arrangedopposite to an inner lateral surface of the first lateral plate (311),an external surface (350 b) of the second magnet (354) is arrangedopposite to an inner lateral surface of the second lateral plate (312),an external surface (350 b) of the third magnet (356) is arrangedopposite to an inner lateral surface of the third lateral plate (313)and an external surface (350 b) of the fourth magnet (358) is arrangedopposite to an inner lateral surface of the fourth lateral plate (314).

The first lateral plate (311) is formed with a first pocket unit (311 a)in order to secure the first magnet (352) to a predetermined position ofthe first lateral plate (311). The first pocket unit (311 a) fixes theexternal surface (350 b) and lateral surfaces (350 c) of the firstmagnet (352). The first pocket unit (311 a) is formed by protruding apart of the first lateral plate (311) from an inner lateral surfacetoward the external surface, where the first magnet (352) is insertedinto the first pocket unit (311 a). For example, the first magnet (352)may be press-fitted into the first pocket unit (311 a). Alternatively,an adhesive may be interposed between the first magnet (352) and thefirst pocket unit (311 a) in order to securely fix the first magnet(352) to the first pocket unit (311 a).

In the exemplary embodiment of the present disclosure, the press-fittingmethod may be categorized into three types based on dimensionalrelationship of the first, second, third and fourth magnets (352, 354,356, 358) and first, second, third and fourth pocket units (311 a, 312a, 313 a, 314 a), that is, a forced press-fitting method where there isno gap, a middle press-fitting method where there is a gap or no gap,and a loose press-fitting method where there is always a gap. In theexemplary embodiment of the present disclosure, all the structuralmethods may be included capable of inhibiting vertical or horizontalmovement of the first, second, third and fourth magnets (352, 354, 356,358) within a predetermined range.

The second pocket unit (312 a) is formed at the second lateral plate(312) in order to fix the second magnet (354) to a predeterminedposition of the second lateral plate (312). The second pocket unit (312a) fixes the external surface (350 b) and lateral surface (350 c) of thesecond magnet (354). The second pocket unit (312 a) is formed byprotruding a part of the second lateral plate (312) from an innerlateral surface to the external surface. For example, the second magnet(354) may be press-fitted into second pocket unit (312 a).Alternatively, an adhesive may be interposed between the second magnet(354) and the second pocket unit (312 a) in order to securely fix thesecond magnet (354) to the second pocket unit (312 a).

The third pocket unit (313 a) is formed at the third lateral plate (313)in order to fix the third magnet (356) to a predetermined position ofthe third lateral plate (313). The third pocket unit (313 a) fixes theexternal surface (350 b) and lateral surface (350 c) of the third magnet(356).

The third pocket unit (313 a) is formed by protruding a part of thethird lateral plate (313) from an inner lateral surface to the externalsurface. For example, the third magnet (356) may be press-fitted intothird pocket unit (313 a). Alternatively, an adhesive may be interposedbetween the third magnet (356) and the third pocket unit (313 a) inorder to securely fix the third magnet (356) to the third pocket unit(313 a).

The fourth pocket unit (314 a) is formed at the fourth lateral plate(314) in order to fix the fourth magnet (358) to a predeterminedposition of the fourth lateral plate (314). The fourth pocket unit (314a) fixes the external surface (350 b) and lateral surface (350 c) of thefourth magnet (358). The fourth pocket unit (314 a) is formed byprotruding a part of the fourth lateral plate (314) from an innerlateral surface to the external surface. For example, the fourth magnet(358) may be press-fitted into fourth pocket unit (314 a).Alternatively, an adhesive may be interposed between the fourth magnet(358) and the fourth pocket unit (314 a) in order to securely fix thefourth magnet (358) to the fourth pocket unit (314 a).

In the exemplary embodiment of the present disclosure, the magnet (350)can be inhibited from being disengaged from the yoke (310) by externalshock or vibration by arranging the first, second, third and fourthpocket units (311 a, 312 a, 313 a, 314 a) on the first, second, thirdand four lateral plates (311, 312, 313, 314) of the yoke (310).

Furthermore, because positions of the first, second, third and fourthmagnets (352, 354, 356, 358) are determined by the first, second, thirdand fourth pocket units (311 a, 312 a, 313 a, 314 a) formed at thefirst, second, third and fourth lateral plates (311, 312, 313, 314), thepositions of the first, second, third and fourth magnets (352, 354, 356,358) are inhibited from being changed or being arranged at positioneddeviated from designated positions.

A magnet support unit (316) may be formed by extending or bending abottom end of the first, second, third and fourth lateral plates (311,312, 313, 314) toward the bottom surface of the first, second, third andfourth magnets (352, 354, 356, 358).

Meanwhile, in order for the first, second, third and fourth magnets(352, 354, 356, 358) from being disengaged from an upper surfaceopposite to the bottom surface of the first, second, third and fourthpocket units (311 a, 312 a, 313 a, 314 a), the yoke (310) may include anadditional magnet support unit extended from the first, second, thirdand fourth pocket units (311 a, 312 a, 313 a, 314 a) to the uppersurface of the first, second, third and fourth magnets (352, 354, 356,358).

Meantime, referring to FIGS. 9 and 10 , the yoke (310) included in thestator (300) may include a curvature yoke plate (370) arranged inparallel with the coil block (190) from a portion corresponding to themagnets (350) to inhibit the magnetic field generated by the coil block(190) from leaking.

Each magnet (350) fixed by the yoke (310) generates a magnetic field,and the rotor (100) is driven by a repulsive force generated by themagnetic field generated by the magnets (350) and the magnetic fieldgenerated by the coil block (19) facing the magnets (350).

Referring to FIG. 8 again, the upper spacer (400) includes an upperplate (411) and a coupling pillar (412). The upper spacer (400) isarranged on the magnet support unit (316), and the second elastic member(220) of the second elastic member (200) is interposed between the upperspacer (400) and the yoke (310).

The upper plate (411) of the upper spacer (400) takes the shape of asquare plate when viewed in a top plane view, and is centrally formedwith an opening (414) for exposing the bobbin (150). The coupling pillar(412) of the upper spacer (400) is protruded in parallel with the bobbin(150) from four corners of the upper plate (411), and the couplingpillar (412) is coupled to the base (420, described later). The base(420) includes pillars (425) coupled to the each coupling pillar (412)of upper spacer (400).

FIG. 11 is a plan view of a yoke and a magnet of VCM according toanother exemplary embodiment of the present disclosure.

The VCM illustrated in FIG. 11 has the substantially same structure asthat of FIGS. 8 to 10 except for the yoke, such that like referencenumerals refer to like elements throughout, and explanations thatduplicate one another will be omitted.

Referring to FIG. 11 , the yoke (310) takes the shape of an pentagonalframe, and mutually facing four lateral plates among eight lateralsurfaces of the yoke (310) are respectively defined as first, second,third and fourth pocket units (311 a, 312 a, 313 a, 314 a), and thefirst, second, third and fourth pocket units (311 a, 312 a, 313 a, 314a) are fixed with the first, second, third and fourth magnets (352, 354,356, 358).

As apparent from foregoing, there is an advantageous effect in that amagnet can be inhibited from moving inside a yoke by forming a pocketunit at the yoke and fixing the magnet at the pocket unit, the magnetcan be inhibited from being disengaged from the yoke by outside shock,the magnet can be secured at a predetermined position and the magnet canbe arranged inside the yoke by automatic facility

FIG. 12 is an exploded perspective view of a VCM according to anexemplary embodiment of the present disclosure, and FIG. 13 is anassembled cross-sectional view of FIG. 12 .

Referring to FIGS. 12 and 13 , a VCM (800) includes a rotor (1200),elastic members (300, 1400) and a stator (600). The VCM (800) mayfurther include a base (1100) and a cover can (700).

The rotor (12100) includes a bobbin (1210) and a coil block (250). Thebobbin (1210) takes the shape of a hollow hole-formed cylinder and ismounted therein with a lens (not shown). The bobbin is alternativelyformed at a periphery with a curvature unit (214) and a planar unit(216). In the exemplary embodiment of the present disclosure, fourcurvature units (214) and planar units (216) are respectivelyalternatively formed.

The curvature unit (214) formed at the periphery of the bobbin (1210) isformed with a bond tank (215) for fixing a coil block (250, describedlater), and the bond tank (215) takes the shape of a recess concavedfrom the curvature unit (214).

Although the exemplary embodiment of the present disclosure illustratedand explained the bond tank (215) formed at the curvature unit (214), itshould be apparent that the bond tank (215) may be formed at the planarunit (216).

Meantime, part of an upper end of each curvature unit (214) formed atthe periphery of the bobbin (1210) is cut out to allow the curvatureunit (214) of the bobbin (1210) to be formed with a stair-cased hitchingsill (214 a), and the bond tank (215) is linked to the hitching sill(214 a).

A support unit (218) is formed at a bottom end of the periphery of thebobbin (1210) for supporting the coil block (250, described later), andis protruded along the peripheral bottom end of the bobbin (1210) in theshape of a rib. The support unit (218) may include a partially cut-outunit (219) through which both ends of the coil block (250, describedlater) can pass.

The coil block (250) included in the rotor (1200) takes the shape of acylinder, and is formed by winding an insulation resin-coated wire suchas enamel resin in the shape of a cylinder. The coil block (250) may bedirectly wound on the periphery of the bobbin (1210). The coil block(250) formed on the periphery of bobbin (1210) is bonded to the bobbin(1210) via an adhesive provided to the bond tank (215). Both ends (252,254) of the coil block (250) arranged on the periphery of the bobbin(1210) are protruded to a bottom surface of the bobbin (1210) throughthe cut-out unit (219) of the support unit (218) formed at the bobbin(1210).

The both ends (252, 254) of the coil block (250) protruded to the bottomsurface of the bobbin (1210) through the cut-out unit (219) of thesupport unit (218) formed at the bobbin (1210) are electricallyconnected to a first elastic member (300) among the elastic members(300, 400, described later). The elastic members (300, 1400) include afirst elastic member (300) and a second elastic member (1400).

The first elastic member (300) is coupled to the bottom surface of thebobbin (12100), and the second elastic member (1400) is arranged on anupper surface of the bobbin (1210). A pair of first elastic members(300) is arranged on the bottom surface of the bobbin (1210), and thepair of first elastic members (300) serves to support the bottom surfaceof the bobbin (1210). Each of the pair of first elastic members (300)arranged at the bottom surface of the bobbin (1210) is electricallyisolated from the other, such that each of the pair of first elasticmembers (300) is not mutually contacted.

Each of the pair of first elastic members (300) coupled to the bottomsurface of bobbin (1210) may be formed by etching process or press workof a conductive metal plate. Each of the pair of first elastic members(300) is symmetrically formed about the bobbin (1210). Each of the pairof first elastic members (300) includes an inner elastic unit (302), anexternal elastic unit (304) and a connection elastic unit (306).

Each inner elastic unit (302) takes the shape of a semi-circular platewhen viewed in a top plane view, and is formed with a through hole (303)coupled to a boss (210-1) formed at the bottom surface of the bobbin(1210). Each inner elastic unit (302) is fixed at the bottom surface ofthe bobbin (1210).

Each inner elastic unit (302) is electrically connected to both ends(252, 254) of the coil block (250). For example, each inner elastic unit(302) is electrically connected to both ends (252, 254) of the coilblock (250) via a solder.

Each of the external elastic units (304) is arranged at a periphery ofthe inner elastic unit (302) and takes the shape of a semi-circularplate when viewed in a top plan view. Each of the external elastic units(304) is formed with a through hole (305) coupled to the boss (130)formed at an upper surface (110) of the base (1100, described later).

Each of the connection elastic units (306) serves to elastically connectthe inner elastic unit (302) and the external elastic units (304), andmay take the shape of a zigzag when viewed in a top plan view in orderto generate elastic force.

In the exemplary embodiment of the present disclosure, the first elasticmember (300) is formed with a terminal unit (310) to be electricallyconnected to an outside circuit substrate. An electric signal providedto the terminal unit (310) is provided to both ends (252, 254) of thecoil block (250) through the pair of first elastic members (310),whereby a magnetic field is generated from the coil block (250).

Meanwhile, an upper surface corresponding to the bottom surface of thebobbin (1210) is such that the second elastic member (1400) may beelastically coupled to the upper surface of the bobbin (1210). Thesecond elastic member (1400) is coupled to a stroke lug formed at ahousing of the stator (described later).

FIG. 14 is a cross-sectional view cut along line I-I′ of FIG. 12 .Referring to FIGS. 12 and 14 , the stator (600) includes a flat magnet(610) and a housing (690). The flat magnet (610) is arranged opposite tothe coil block (250) wound on the bobbin (1210), and includes aplurality of magnets.

In the exemplary embodiment of the present disclosure, each of the flatmagnets (610) takes the shape of a plate, and four flat magnets (610)are mutually vertically arranged. Each of the flat magnets (610) takesthe shape of a cuboidal plate formed with mutually facing long sides(612) and mutually facing short sides (614).

The flat magnet (610) may include a single flat magnet formed with an Npole and an S pole, or a stacked flat magnet in which at least twosingle magnets each stacked with an N pole and an S pole are stacked.Alternatively, the flat magnet (610) may include a four-pole flat magnetformed with N pole-S pole-N pole-S pole.

In the exemplary embodiment of the present disclosure, a surface of theflat magnet (610) opposite to the coil block (250) is defined as a frontsurface (601), and a surface opposite to the front surface (601) of theflat magnet (601) is defined as a rear surface (602).

The housing (690) functions to secure the flat magnet (610) whereby theflat magnet (610) faces the coil block (250). In the exemplaryembodiment of the present disclosure, the housing (690) may take theshape of a bottom surface-opened cuboidal box. The housing (690)includes a upper plate (620) and a lateral plate (630), and the flatmagnet (610) is fixed at each lateral plate (630).

The upper plate (620) of the housing (690) takes the shape of a squareplate, for example, and is centrally formed with an opening (621)exposing a lens mounted at the bobbin (1210). The lateral plate (630) ofthe housing (690) is extended to a direction encompassing the bobbin(1210) from four edges of the upper plate (620), whereby the housing(690) takes the shape of the bottom surface-opened cuboidal box.

Meanwhile, a stopper unit (628) is protruded from an inner lateralsurface formed by the opening (621) formed at the upper plate (620), andthe stopper unit (628) is formed at a position corresponding to eachhitching sill (214 a) formed at the curvature unit (214) at theperiphery of the bobbin (1210). The stopper unit (628) is brought intocontact with the hitching sill (214 a) of the bobbin (1210) to restricta stroke length of the bobbin (1210).

In the exemplary embodiment of the present disclosure, the stopper unit(628) may be formed with a curved surface having a similar or samecurvature as that of the periphery of the bobbin (1210), when viewed ina top plan view.

Stroke lugs (640) are protruded from the upper plate (620) of thehousing (690). Each of the stroke lugs (640) is formed at each diagonalcorner of upper plate (620), and may be formed at each corner of theupper plate (620). The stroke lugs (640) serve to secure a stroke spaceand to fix the second elastic member (400).

The stroke lug (640) formed at each corner of upper plate (620) isformed in a pair, and the pair of stroke lugs (640) is symmetricallyformed about the center of the stroke lug (640).

In the exemplary embodiment of the present disclosure, the pair ofstroke lugs (640) may be formed with a shape similar to a semi-circularpillar. Alternatively, the pair of stroke lugs (640) may be formed withvarious shapes including a square pillar and a polygonal pillar.Although the exemplary embodiment of the present disclosure illustratedand explained that the pair of stroke lugs (640) is symmetrically formedat each corner of upper plate (620) of the housing (690), alternatively,it should be apparent that the pair of stroke lugs (640) may beasymmetrically formed at each corner of upper plate (620) of the housing(690).

Meanwhile, the upper plate (620) of the housing (690) is formed with abond tank unit (625) along a circumference of the stroke lug (640) inthe shape of a trench, and the bond tank unit (625) is provided with anadhesive, and the second elastic member (400) is bonded to the upperplate (620) of the housing (690) via the adhesive. A coupling lug (627)is formed at a position adjacent to the stroke lug (640) of the upperplate (620) at the housing (690).

The coupling lug (627) is coupled to the housing (690) to a directiondesignated by the second elastic member (400), and each of thediagonally formed coupling lugs (627) formed at the upper plate (620) ofthe housing (690) is asymmetrically formed based on the center of theupper plate (620) in order to inhibit the second elastic member (400)from being coupled to the housing (690) to a direction not designated bythe second elastic member (400).

A center of each lateral plate (630) of the housing (690) is formed witha through hole (635) through which each lateral plate (630) passes, andthe flat magnet (610) is coupled to the lateral plate (630) of thehousing (690) using an accommodation hole (635).

FIG. 15 to FIG. 17 illustrates front views of lateral plate of FIG. 14 .

Referring to FIGS. 12, 14 and 15 , each lateral plate (630) of thehousing (690) includes a disengagement prevention unit (636) to inhibitthe flat magnet (610) accommodated in the accommodation hole (635) ofeach lateral plate (630) from being disengaged to a direction facing thecoil block (250).

The disengagement prevention unit (636) inhibits the operationimperfection of the rotor (200) that is generated by the flat magnet(610) that is disengaged to a direction facing the coil block (250) tointerfere with the coil block (250).

The disengagement prevention unit (636) is extended from an innerlateral surface (631) of the lateral plate (630) into the accommodationhole (635), and is formed with a thickness thin enough not to interferewith the coil block (250). The disengagement prevention unit (636) isbrought into contact with both edges of the front surface (601) of theflat magnet (610), for example. To this end, the disengagementprevention unit (636) is protruded from the inner lateral surface (631)of the lateral plate (630) toward both edges of the front surface (601)of the flat magnet (610).

In the exemplary embodiment of the present disclosure, in a case thedisengagement prevention unit (636) is extended from an inner lateralsurface (631) of the lateral plate (630) into the accommodation hole(635), the thickness of the flat magnet (610) is not affected bythickness of the disengagement prevention unit (636), such that thethickness of the flat magnet (610) can be formed with the substantiallysame thickness of the lateral plate (630). In the exemplary embodimentof the present disclosure, an external surface of the lateral plate(630) is arranged on the same planar surface as that of the rear surface(602) of the flat magnet (610).

As illustrated in FIG. 15 , it should be apparent that the disengagementprevention unit (636) is formed in parallel with the upper plate (620)of the housing (690), formed in parallel with the long side (612) of theflat magnet (610) and formed to a second direction (SD) perpendicular toa first direction (FD).

As illustrated in FIG. 17 , it should be apparent that the disengagementprevention unit (636) is parallel with an axial direction of the bobbin(250), parallel with the first direction (FD) parallel with the shortside (614) of the flat magnet (610) and the upper plate (620) of thehousing (690), and parallel with the long side (612) of the flat magnet(610) and the second direction (SD) perpendicular to the first direction(FD).

FIG. 18 is a cross-sectional view of a disengagement prevention unit ofa housing according to an exemplary embodiment of the presentdisclosure.

Referring to FIG. 18 , a disengagement prevention unit (637) formed atthe lateral plate (630) of the housing (690) is protruded from anaccommodation surface (635 a) formed by the accommodation hole (635)penetrating each lateral plate (630), and the disengagement preventionunit (637) is thinner than the lateral plate (630) to support both edgesof the front surface (601) of the flat magnet (610).

The thickness of each flat magnet (610) is formed with a thickness minusthe thickness of the disengagement prevention unit (637) from thethickness of the lateral plate (630). Furthermore, in the exemplaryembodiment of the present disclosure, an external surface of the lateralplate (630) is arranged in the same planar surface as that of the rearsurface (602) of the flat magnet (610).

FIG. 19 a cross-sectional view of a disengagement prevention unit of ahousing according to another exemplary embodiment of the presentdisclosure.

Referring to FIG. 19 , the disengagement prevention unit (637) formed atthe lateral plate (630) of the housing (690) is protruded from anaccommodation surface (635 a) formed by the accommodation hole (635)penetrating each lateral plate (630), and the disengagement preventionunit (637) is thinner than the lateral plate (630).

In a case the disengagement prevention unit (637) formed at the lateralplate (630) of the housing (690) is protruded from an accommodationsurface (635 a) formed by the accommodation hole (635), the thickness ofthe flat magnet (610) is affected by the disengagement prevention unit(637).

In the exemplary embodiment of the present disclosure, in order toinhibit the thickness of the flat magnet (610) from being reduced by thedisengagement prevention unit (637), the flat magnet (610) contactingthe disengagement prevention unit (637) is formed with an accommodationgroove (613) that accommodates the disengagement prevention unit (637).The flat magnet (610) can be formed with a thickness substantially sameas that of the lateral plate (630) by forming the accommodation groove(613) at the flat magnet (610) regardless of the disengagementprevention unit (637).

Furthermore, in the exemplary embodiment of the present disclosure, theexternal surface of the lateral plate (630) is arranged on the sameplanar surface as that of the rear surface (602) of the flat magnet(610). The lateral plate (630) of the housing (690) is formed with acoupling groove (626) coupled to each coupling pillar (120) formed ateach corner of upper surface (110) of the base (100, described later).

A socket groove (638) is formed across the accommodation hole (635) ofthe pair of lateral plate (630) opposite to the lateral plates (630) ofthe housing (690), and the VCM (800) is coupled to the outside circuitsubstrate using the socket groove (638).

The cover can (700) includes a cover can upper plate (710) and a covercan lateral plate (720). In the exemplary embodiment of the presentdisclosure, the cover can (700) may be formed by processing a metalplate capable of blocking a magnetic field or blocking a hazardouselectromagnetic wave.

The cover can upper plate (710) includes an opening corresponding to thehollow hole of the bobbin (210), and an inner lateral surface of thecover can upper plate (710) is brought into contact with an uppersurface of each stroke lug (640) protruded from each corner of the upperplate (620) of the housing (690).

The cover can lateral plate (720) is extended from an edge of the covercan upper plate (710) to a direction encompassing the lateral plate(630) of the housing (690), and is brought into contact with a rearsurface (602) of each flat magnet (610) coupled to the accommodationhole (635) of the lateral plate (630) at the housing (690).

The flat magnet (610) is inhibited from moving backward or forward fromthe lateral plate (630) of the housing (690) by the contact between therear surface (602) of the flat magnet (610) and the inner lateralsurface of the cover can lateral plate (720).

The cover can lateral plate (720) blocks a magnetic field leaked fromthe flat magnet (610) or a hazardous electromagnetic wave. The rearsurface (602) of the flat magnet (610) and the cover can lateral plate(720) may be mutually adhered by a bond.

In a case the lateral plate (630) of the housing (690) is formed withthe socket groove (638), the cover can lateral plate (720) encompassingthe lateral plate (630) of the housing (690) is formed with a cut-outunit (725) exposing the socket groove (638).

The base (200) functions to secure the bobbin (210), the first elasticmember (300), the stator (600) and the cover can (700). The base (100)takes the shape of a cuboidal plate centrally formed with an opening(105), and is mounted at a rear surface thereof with an IR (Infrared)filter formed at a front side of an image sensor module. The IR filterfunctions to remove the infrared included in the outside light.

An upper surface (110) opposite to the rear surface of the base (100) isarranged with a rear surface of the bobbin (210) coupled to the firstelastic member (300). Four corners of the upper surface (110) of thebase (100) are formed four coupling pillars (120) perpendicularlyprotruded relative to each upper surface (110), and each coupling pillar(120) is coupled to the coupling groove (626) of the housing (690).

The upper surface (110) of the base (100) is formed with bosses (130)coupled to the first elastic member (300). Furthermore, the base (100)is formed with through holes (140) through which the terminal units(310) formed at the first elastic member (300) pass.

As apparent from the foregoing, the present disclosure has anadvantageous effect in that a flat-shaped flat magnet opposite to a coilblock and generating a magnetic field is formed at an accommodation holeformed at a lateral plate of a housing, and a disengagement preventionunit is formed at the lateral plate to inhibit the flat magnet frombeing disengaged to enhance the performance of VCM.

FIG. 20 is an exploded perspective view of a VCM according to anexemplary embodiment of the present disclosure, FIG. 21 is an explodedperspective view of a flat magnet and a bottom spacer in FIG. 20 , FIG.22 is an assembled perspective view of a flat magnet and a bottom spacerin FIG. 21 , and FIG. 23 is a front view of a flat magnet coupled to thebottom spacer of FIG. 22 .

Referring to FIGS. 20 through 23 , a VCM (800) includes a rotor (100), astator (200), an elastic member (300) and a base (400). The VCM (800)may further include an upper spacer (500) and a cover can (600). Therotor (100) includes a bobbin (110) and a coil block (120).

The rotor (100) includes a lens, and distances the embedded lens from animage sensor secured to the base (400) to change a gap between the lensand the image sensor.

The bobbin (110) takes the shape of a hollow hole-formed cylinder, andis secured therein with a lens. In order to secure the lens to an innersurface of the bobbin (110), the inner surface of the bobbin (110) maybe formed with a screw thread. A periphery of the bobbin (110) is formedwith four planar units (112), for example, and each of the four planarunits (112) is distanced from the other at an equal predetermined gap.

Meanwhile, a bottom end of the periphery of the bobbin (110) is formedwith a support unit (114) for supporting the coil block (120, describedlater), and the support unit (114) is formed by protruding from thebottom end of the periphery of the bobbin (110).

The coil block (120) is formed by winding an insulation resin (such asenamel resin) coated long wire. The coil block (120) takes the shape ofa barrel arranged at the periphery of the bobbin (110). The coil block(120) takes the shape of a square barrel with upper surface and a bottomsurface opened.

In a case a current is applied to the coil block (120) wound with a wirein the shape of a cylinder, a magnetic field is generated from the coilblock (120). The coil block (120) inserted into the periphery of thebobbin (110) includes four planar surfaces (122) which are same as thefour planar units (112) of the bobbin (110), and four curvatures (124)connecting the planar surfaces (122).

Referring to FIGS. 21 and 22 , the stator (200) includes a flat magnet(210) and a magnet fixing member (250). The flat magnet (210) may takethe shape of a cuboidal plate, for example. A front surface (212)opposite to the coil block (120) on the flat magnet (210) of cuboidalshape is arranged opposite to each planar surface (122) of the coilblock (120), whereby the number of flat magnets (210) is same as that ofthe planar surface (122) at the coil block (120).

In the exemplary embodiment of the present disclosure, each of the fourflat magnets (210) is arranged opposite to each of the four planarsurfaces (122), and each of the four flat magnets (210) is mutuallyperpendicularly arranged. Each of the flat magnets (210) may be atwo-pole flat magnet or a four-pole flat magnet.

The magnet fixing member (250) serves to secure a bottom elastic member(310) of the elastic member (300, described later) and the flat magnets(210) as well. The magnet fixing member (250) includes a frame unit(260), a pillar unit (270) and a fixing unit (280) in order to fix thebottom elastic member (310) and each of the flat magnets (210).

The frame unit (260) supports each bottom surface of four flat magnets(210), and takes the shape of a square frame having an opening whenviewed in a top plan view, in order to support the bottom surface (211)of the four flat magnets (210).

The pillar unit (270) is protruded from an upper surface of the frameunit (260) opposite to both lateral surfaces (213) of each flat magnet(210). In the exemplary embodiment of the present disclosure, each ofthe pillar unit (270) is protruded from the upper surface of the frameunit (260) corresponding to the adjacent pair of flat magnets (210).Referring to FIG. 21 , The pillar units (270) can include a first pillarunit (270 a), a second pillar unit (270 b), a third pillar unit (270 c),and a fourth pillar unit (270 d), and each of the pillar units (270 a,270 b, 270 c, 270 d) is protruded from each corner of the upper surfaceof the frame unit (260), respectively. The pillar units (270) can eachinclude a first end (291) and a second end (292) opposite to the firstend (291), the second end (292) being closer to the frame unit (260)than is the first end (291). A first direction from the first end (291)of the first pillar unit (270 a) and the first end (291) of the secondpillar unit (270 b) to the second end (292) of the first pillar unit(270 a) and the second end (292) of the second pillar unit (270 b) isclosed by the frame unit (260), and a second direction from the secondend (292) of the first pillar unit (270 a) and the second end (292) ofthe second pillar unit (270 b) to the first end (291) of the firstpillar unit (270 a) and the first end (291) of the second pillar unit(270 b) is opened. A thickness of the first end (291) of the pillarunits (270) can be smaller than a thickness of the second end (292) ofthe pillar units (270). Each pillar unit (270) can include a first outerlateral surface (294) that faces a first lateral plate of the cover(600), a second outer lateral surface (295) facing a second lateralplate of the cover (600), and a third outer lateral surface (296) thatconnects the first (294) and second (295) outer lateral surfaces andfaces a corner part of the cover (600).

Each of the pillar units (270) opposite to both lateral surfaces (213)of each flat magnet (210) is formed with an inclined guide unit (275) toallow the flat magnet (210) to be smoothly inserted.

While the flat magnet (210) is supported to the upper surface of theframe unit (260), corners (214) formed by a bottom end (276) of theguide unit (275), a lateral surface (213) and the bottom surface (211)of the flat magnet (210) meet each other. In a case the distal end ofthe guide unit (275) and the corners (214) of the flat magnet (210)meet, the flat magnet (210) is fixed to a designated position of thebottom spacer (200).

Meanwhile, as the guide unit (275) is inclined, the flat magnet (210)can be arranged on the frame unit (260) along the guide unit (275)formed at each of the pair of pillar units (270) as illustrated in FIG.4 , in a case the flat magnet (210) is arranged on the upper surface ofthe frame unit (260).

Alternatively, in a case the inclined guide unit (275) is not formed atthe pillar unit (270) formed at the frame unit (260), it is difficult toaccurately insert a very small-sized flat magnet (210) into a verysmall-sized pillar unit (270) to generate frequent assembly defects andto take a lot of time in assembly.

The fixing unit (280) is extended from an inner lateral surface of eachpillar unit (270) formed at the frame unit (260) to a direction facingthe front surface of the flat magnet (210), and each flat magnet (210)is supported by the fixing unit (280).

The elastic member (300) includes a bottom elastic member (310) and anupper elastic member (350). Two bottom elastic members (310) are formedin a pair. The bottom elastic member (310) formed in a pair ishereinafter defined as a first bottom elastic member (314) and a secondbottom elastic member (319).

The first and second bottom elastic members (314, 319) include externalelastic units (311, 315) formed in the shape corresponding to that ofthe frame unit (260) of magnet fixing member (250), inner lateralelastic units (312, 317) secured to the bottom surface of the bobbin(110) and connection elastic units (313, 318) connecting the externalelastic units (311, 315) and the inner lateral elastic units (312, 317).The connection elastic units (313, 318) elastically support the bobbin(110).

In the exemplary embodiment of the present disclosure, the inner lateralelastic units (312, 317), the external elastic units (311, 315) and theconnection elastic units (313, 318) of the first and second bottomelastic members (314, 319) are integrally formed.

Meanwhile, the external elastic units (311, 315) of the first and secondbottom elastic members (314, 319) are respectively formed with terminalunits (311 a, 315 a), and the terminal units (311 a, 315 a) are bentfrom the external elastic units (311, 315) to the bottom. The upperelastic member (350) elastically supports the bobbin (110) by beingcoupled to the upper surface of the bobbin (110).

The upper elastic member (350) includes a square frame-shaped externalelastic unit (352), and an inner lateral elastic unit (354) coupled tothe upper surface of the bobbin (110) and a connection elastic unit(356) connecting the external elastic unit (352) and the inner lateralelastic unit (354).

Four corners of the external elastic unit (352) of the upper elasticmember (350) are arranged on an upper surface of each pillar unit (270)of the magnet fixing member (250). The base (400) secures the rotor(100), the stator (200) and the bottom elastic member (310) of theelastic member (300). The base (400) takes the shape of a square plate,and is formed with an opening (410) corresponding to the hollow hole ofthe bobbin (110).

An edge of an upper surface (401) of the base (400) is formed with a lug(403) contacting the external elastic units (311, 315) of the bottomelastic member (310), and an edge of the upper surface (401) of the base(400) is formed with a coupling groove (404) coupled to the coupling lugprotruded from the bottom surface of the frame unit (260) of the magnetfixing member (250).

The bottom elastic member (310) is interposed between the frame unit(260) of the magnet fixing member (250) and the lug (403) of the base(400), and the bottom elastic member (310) is secured by the base (400)and the frame unit (260) of the magnet fixing member (250).

The upper spacer (500) is arranged at an upper surface of the upperelastic member (350). The upper spacer (500) is formed in a shapecorresponding to the frame unit (260) of the magnet fixing member (250)and is a size corresponding to that of the frame unit (260). A couplinglug (510) is formed at a position corresponding to the pillar unit (270)of the magnet fixing member (250), and the coupling lug (510) formed atthe upper spacer (500) is coupled to a coupling hole (275 a) formed atthe upper surface of the pillar unit (270) of the magnet fixing member(250).

The upper elastic member (350) is coupled to the magnet fixing member(250) and the upper spacer (500) by coupling between the coupling hole(275 a) formed at the pillar unit (270) of the magnet fixing member(250) and the coupling lug (510) of the upper spacer (500).

The cover can (600) includes an upper plate (610) and a lateral plate(620). The upper plate (610) is formed with an area substantially thesame as that of the base (400), and is centrally formed with an openingexposing the bobbin (110). The lateral plate (620) is extended to adirection facing the base (400) from an edge of the upper plate (610) tobe coupled to the base (400).

In inner lateral surface of the lateral plate (620) is brought intocontact with a rear surface of the flat magnet (210) fixed to the magnetfixing member (250), and the lateral plate (620) functions as a yoke.

As apparent from the foregoing, the VCM according to the exemplaryembodiment of the present disclosure has an advantageous effect in thata frame unit and a pillar unit protruded from the frame unit are formedon a bottom spacer, a magnet is arranged at the frame unit, and themagnet is fixed by protruding a guide unit from the pillar unit toreduce the number of constituent elements and assembling processeswithout using a yoke for fixing the conventional magnet and to increasean aperture of a bobbin and a lens mounted at the bobbin.

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it should be understood that numerousother modifications and embodiments can be devised by those skilled inthe art that will fall within the spirit and scope of the principles ofthis disclosure. More particularly, various variations and modificationsare possible in the component parts and/or arrangements of the subjectcombination arrangement within the scope of the disclosure, the drawingsand the appended claims.

1. A voice coil motor, comprising: a yoke comprising an upper plate anda lateral plate extending from the upper plate; a bobbin disposed in theyoke; a fixing member disposed between the yoke and the bobbin; a coildisposed on the bobbin; and a magnet disposed between the coil and thelateral plate of the yoke and facing the coil, wherein the fixing membercomprises a body unit, and a coupling unit extending from the body unit,wherein the magnet is disposed on the body unit of the fixing member andprotrudes downwardly below the coupling unit of the fixing member,wherein the coupling unit extends from the body unit along the lateralplate of the yoke, and both sides of the magnet are coupled to thecoupling unit, wherein the lateral plate of the yoke comprises a firstlateral plate, a second lateral plate, and a first corner part disposedbetween the first lateral plate and the second lateral plate, whereinthe coupling unit comprises a first coupling unit disposed at a positioncorresponding to that of the first corner part of the yoke, wherein thefirst coupling unit comprises a first surface coupled with the firstlateral plate of the yoke, a second surface coupled with the secondlateral plate of the yoke, and a third surface connecting the firstsurface and the second surface and disposed at a position correspondingto that of the first corner part of the yoke, and wherein the thirdsurface of the first coupling unit is spaced apart from the first cornerpart of the yoke.